And rafael guasta



'of contact; we have found that three parts WALLACE CLEMENT SABINE, OF BOSTON, MASSACHU VINO, OFBAY SHORE, NEW YORK; JANE D. KELL WALLACE C. SABINE, DECEASED.

SOUND-ABSORBIN G MATERIAL Original No. 1,197,956,dated September l2, 1916, Seri for reissue filed July 24, 1

To all whom. it may concern.'

Be it known that we, WALLACE CLEMENT SABINE and RAFAEL GUAsTAviNo, citizens of the United States, residin respectively, at Boston, in the county of uffolk and State of Massachusetts, and Bay Shore, county of Suffolk, and State of New York, have invented certain new and useful Im rovements in Sound-Absorbing Materia s for Walls and Ceilings, of which the following is Aa specification.

r1 he object of our invention is to provide a structural lmaterial suitable for facing walls and ceilings in auditoriums and the like, which shall correct certain types of acoustical difiiculties by the preventionof excessive reverberation and echo and injurious focusin of sound.

In our atent No. 1,119,543, issued December- 1, 1914:, we disclosed primarily a ceramic masonry material suitable for this purpose. Ceramic materials are, however, expensive and diicult to manufacture, as the'porous Vblocks described in saidv patent have a tendency to warp when subjected to the heat necessary to fuse the flux, which when cooled, gives strength and solidarity to the finished material or tile, and the object of the present invention is to provide a material suitable for the purposes described, which will be easily and cheaply manufactured.

In the accompanying drawings Figure 1 is an exaggerated sectional view illustrating the primary embodiment of the invention, and r l Fig. 2 is a sectional view illustrating that embodiment of the invention wherein separate layers of different grades are employed to rovide a graded porosity.

ur process of manufacture is as -follows A given quantity of sand, crushed stone, brick, or similar material,` consisting of fine particles of suitable size, are mingled with a sufficient quantity of binding material, as for instance, Portland cement, to secure the particles firmly to each other at the points of sand which will 'just'pass through a sieve, about twelve meshes to"I the inch, and -one part of Portland cement produce satisfactory results. If Portland -cement is used,

\ the requisite quantityof water must also be supplied to 'render kthe cement active. After lof the improved material is shown in'the ac- 'sounds of different pitches is dependent to i a very large extent upon the dimensions of sums, AND RAFAEL oUAsTA-- Y SABINE :ExEcUraIx or SAID' Fon WALLS AND cEILiNes.

Specification of Reissued Letters Patent. Reissued NV 239 1920' a1 No. 60,225, filed November 8, 1915. Application 918. Serial No. 246,613.

thesev materials have bee they are placed in a su cement is allowed to set, thereby securing the particles'-to each other with irregular lntercommunicating pores of variant dimenn sions between the particles, which openly penetrate the exposed finished face ofl the material.

From the foregoing it will be apparent that the essential feature of the present in vention is the use of material graded to a substantially uniform size, so thatfiner. grades of material which .would otherwise fill into the pores of the finished article are eliminated. The ideal condition would be materials which are graded to the same size, but in the practical carrying forward of the invention the grading within 'two or three meshes of screens, so that all of the material isof a substantially uniform size, is sufficient for the purpose. vIn this connection the purpose of the present invention is to obtain fine particles of sand or various other granular materials, such for instance, aspumice, which are so graded that when employed in mass with a relatively small quantity of cement will have only limited points of contact, leaving pores or interstices between, and at these points of Contact, the cement will act as a binding agent without in any way filling or obstructin free communication between thepores. This characteristic nI thoroughly mixed, itable mold and the companying drawings in which Fig. 1 is a-=90 greatly exaggerated sectional view, showing one general size of granules throughout, and Fig. 2 is also an enlarged sectional view illustrating separate layers4 of different grades to provide agraded porosity.

AIn carrying forward this improved process, the new articleresulting therefrom embodies, as hereinbefore indicated the distinguishing characteristic of the article covered by our former Patent No. 1,119,543, namely, that of intercommunicating pores extending throughout the mass andvopenly penetrating vthe exposed finished surface. l

The power of our product to absorb the poresbetween the-particles of which it is composed, and the dimensions yof these pores are largely dependent upon the dimensions ofthe particles; in other words, mate# rial-composed of comparatively coarse particles is better adapted-for the absorption of sounds of a low pitch, Whereas material comf posed of finer particles is better adapted for 'A or ceilings.

the absorption of sounds of higher pitch. W'e `have determined by carefully ccnducted scientific tests that a graded porosity, with the larger pores in the front and the .smaller pores in the rear increases the'range 1n pitch over which our product is acoustically absorbed, and also increases its total absorbing power. y

A product of thls type may be produced by partially filling a mold with sand of the desired Size, mixed with cement and water, allowing it to partially set, and then filling the mold with coarser sand, also mixed nwith cement and Water. The material may also lbe made by forming the inermixture into the desired shape and then forming the coarser mixture into the desired shape while in contact with the finer mixture, without placing the material .in a mold.

Carefully conducted scientific tests have also shown that our finished productmanufacturedaccording to our process above described. will absorb much in excess of 15% of sounds lying inthe pitch between the middle C and the third octave above' 'crushed brick and lime or plaster of Paris,

may be used without departing from the spirit of our invention.

We claim l. A soundabsorbent material for Walls, ioors, and ceilings, consisting of particles of body material graded t approximately uniform size and bonded to each other at `their points of contact.

2. A sound-absorbent material adapted lto be secured to and form the exposed iinished face of walls, fioors and ceilings, consisting of particles'of body material graded to approximately uniform size and bonded to each other at their points of contact.

3. A sound absorbent material for walls, floors and ceilings, consisting of particles of. body material graded to approximately uniform size and bonded to each other at their points of contact, the size of the particles being such that When so bonded together the interstices between the particles possess the propertyof absorbing in excess of fifteen per centum of sounds lying in the structure and 'attached thereto, an exposed layer of sound-absorbent material consist.- ing of particles of body material graded to approximately uniform size and bonded to each` otherat their points of contact.

6. A sound-absorbent `material for walls, floors and ceilings composed of particles of body material bonded to each other at limited points of contact, thereby providing poresexpanding and contracting in crosssection, which intercommunicate and openly penetrate the exposed surface;the.

said body particles being graded to approximately uniform size so as to produce pores of such variant proportional dimensions as to possess the property of absorbing in excess of fifteen per centum of sound lying in the pitch between middle C and the third octave above middle C.

7. A sound absorbing material for Walls and-ceilings consisting of a body of graded porosity having the larger pores in and adjacent the front finished surface and the smaller pores in rear of the larger pores.

8. A sound absorbing material for walls and ceilings consisting of a porous body of relatively fine and coarse particles of material arranged in separate layers to provide a graded porosity.

9. A sound-absorbent material for walls, floors and ceilings consisting of particles of body .material and a, binding substance bonding said particles to `each other only at their points of contact sdas'pto form a cellular material.

l0. A sound-absorbent material adapted to be secured to and form the exposed finished face of Walls7 floors and ceilings, consisting of particles of body .material and a binding substance bonding said 'particles to each other only at their points of contact so as to formA a cellular material.

11. A sound-absorbent material for walls, oors and ceilings consisting of particles of. body material bonded to each other only at their points of contact, the size of the particles being such that when so bonded together the interstices between the particles possess the property of absorbing in excess of fifteen per cent'. of sounds.

l2. A sound-'absorbent material for walls,

ioors and c eilings consisting of particles. of body material bonded to each other at limited points of contact thereby providing Drafman pores which intercommunicate and openly penetrate the exposed surface and which possess the property of absorbing in excess of fifteen per cent. of sounds.

13. The method of producing a sound absorbing material of the kind described which consists in providing particles ot' material with a coating of binding substance and bonding said coated particles to each other at their points of Contact only in 10 the form of a cellular sound absorbent material.

In testimony whereof We hereunto affix our signatures. WALLACE CLEMENT SABINE.

RAFAEL GUASTAVINO. 

